I need to finish "int evaluate(string exp)" What am I missing to return the proper results? For example I needCode:#include <iostream>#include <stack> #include <string> using namespace std; void printMenu(); int evaluate(string exp); int main() { char choice; int result; string line; printMenu(); choice = 'Z'; do { cout << "What action would you like to perform?\n"; cin.get(choice); cin.ignore(20, '\n'); //to flush '\n' choice = toupper(choice); switch(choice) { case 'E': cout << "Enter an arithmetic expression:" << endl; getline(cin, line); result = evaluate(line); cout << "The evaluated value is: " << result << endl; break; case 'Q': //Quit break; case '?': //Display Menu printMenu(); break; default: cout << "Unknown action\n"; break; } } while (choice != 'Q'); return 0; } //Print the menu to a user void printMenu() { cout << "Choice\t\tAction\n"; cout << "------\t\t------\n"; cout << "E\t\tEnter an arithmetic expression to evaluate\n"; cout << "Q\t\tQuit\n"; cout << "?\t\tDisplay Help\n\n"; return; } //The evaluate function takes a string containing an arithmetic expression, //evaluates it,and returns its result int evaluate(string exp) { stack<char> parStack; stack<int> numStack; stack<char> opStack; int j = exp.size(); int i=0; char x; while (i<j) { if(exp[i] == '(') { parStack.push(exp[i]); cout << exp[i] << endl; } if((exp[i]='0') || (exp[i]='1') || (exp[i]='2') || (exp[i]='3') || (exp[i]='4') || (exp[i]='5') || (exp[i]='6') || (exp[i]='7') || (exp[i]='8') || (exp[i]='9')) { numStack.push(exp[i]); } if((exp[i] = '+') || (exp[i] = '-') || (exp[i] = '*') || (exp[i] = '/') || (exp[i] = '%')) { opStack.push(exp[i]); } i++; }(((1+2)/3)*(6-4)) to return 2.